Sympathetic pharmacological denervation in ageing rats: effects on ovulatory response and follicular population

Abstract

The present study analyses the participation of ovarian innervation during reproductive senescence. We use the model of acute peripheral pharmacological sympathetic denervation with guanethidine in young (3 months old), middle-aged (12 months old) or old (18 months old) rats with spontaneous or induced ovulation. Ovarian levels of norepinephrine (NE) were measured by HPLC and the oestrous cycle, the number of ovulating animals and the percentage of atretic follicles were also assessed. Aged animals showed a progressive reduction in ovulatory capacity and an increase in ovarian NE content. Acute denervation increased the percentage of healthy follicles in 12- and 18-month-old rats compared with control adult animals. Combined treatment of denervation plus stimulation with gonadotrophins doubled the number of ova shed in young adult rats and restablished a partial ovulation in 12-month-old rats. The results suggest that ovarian noradrenergic innervation plays a modulator role in ovarian physiology during the ageing ovary process. The action of ovarian noradrenergic innervation seems to be associated with folliculogenesis and the ovarian response to gonadotrophins.